Unit 3 Review Questions Flashcards
What are diuretics?
Compounds that cause fluid loss through increased urine volume.
-caffiene due to vasdialation in nephron
-alcohol due to ADH inhibition
high glucose levels
lasix which decrease the medullary osmotic gradient or prevent it’s formation
Discuss the anatomy of the oral cavity. What type of digestion occurs here?
NKSSE
contains teeth and tongue
mostly mechanical digestion, small amount of chemical digestion
How does gastric filling, mixing, and emptying occur?
Filling: reflexive relaxation coordinated by swallowing center of the brain stem. Stress-relaxation response of smooth muscle
Peristaltic waves: mix food with gastric juice to create chyme. More powerful near pylorus
Emptying: peristaltic waves force 3ml of chime through pyloric sphnicter. Empties in 2-4 hours. Carb rich exits first, lipid rich leaves last
What structures make the renal corpuscle?
glomerulus and bowman’s capsule (parietal layer and visceral layer (podocytes)
Discuss the structures of the filtration membrane and how they are specialized for their function.
fenestrated simple squamous epithelium of glomeruler capillary
shared basement membrane
slit membrane between pedicels of podocytes
very permeable to allow filtrate out of blood
Carbohydrate Digestion
Starch and disaccharides ingested
oral cavity: Salivary amylase digests carbs down to oligosaccharides, dextrin, and disaccharides
small intestine:
-pancreatic amylase breaks them down to smaller oligosaccharides and disaccharides (lactose, sucrose, and maltose)
-Brush border enzymes alpha-dextrinase, lactase, sucrase, and maltase break them down into glucose, fructose, and galactose (monosaccharides)
-Absorbed by enterocytes and brought back to the liver through the hepatic portal vein
Describe the structure and function of the pharynx
Pharynx-functions in swallowing(deglutition). Voluntary oral phase, pharyngeal phase and esophageal phase controlled by medulla
- Discuss the 3 stages of gastric regulation.
- cephalic phase
-stimulatory events: smell, thought, taste, sigh of food
-medulla+hypothalamus->vagus nerve->increased secretions
-inhibited by illness, SNS, or disgust - Gastric phase
-stimulatory events: distension of the stomach from bolus, proteins in food, alkaline environment, or caffeine
-enteroendocrine cells secrete gastrin to increase gastric juice
-inhibited by SNS - Intestinal phase
-brief stimulatory event: enteroendocrine cells in the duodenum secrete intestinal gastrin to increase gastric juice
-inhibitory event: duodenum enteroendocrine cells secrete cholecystokinin and scretin when duodenum is full to decrease gastic juices.
Protein digestion
Stomach: pepsin breaks them down into large polypeptides
small intestine:
-Pancreatic enzymes trypsin, chymotrypsin, and carboxypeptidase break them down into small polypeptides and dipeptides
-Brush border enzymes carboxypeptidase, aminopeptidase, and dipeptidase break them down into amino acids
-Absorbed by enterocytes and takes to liver via hepatic portal vein
Submucosa
loose areolar connective tissue with blood and lymph vessels, elastic fibers, nerves, glands, and malt. submucosal nerve plexus.
Discuss the importance of bacterial flora.
Ferment indigestible carbs and mucus
release gases that create flatus
synthesize vitamin K
keep pathogenic bacteria in check
may influence weight, mood, and susceptibility to some diseases like diabetes
What is the countercurrent exchanger and where is it located
The vasa recta, preserves the osmotic gradient in the renal medulla
What enzymes are secreted by the pancreas?
Protein:
trypsinogen->trypsin (converted by brush border enzyme enteropeptidase
chymotrypsinogen->chymotrypsin
procarboxypeptidase->carboxypeptidase
Pancreatic amylase (carbs)
pancreatic lipase (fats)
ribonuclease and deoxyribonuclease (RNA and DNA)
What is saliva and how is salivation controlled?
-secrete slightly acidic saliva that contains water, ions, salivary amylase, proteins, mucin, lysozyme, metabolic wastes, and IgA.
-minor glands keep mouth moist
-stimuli such as taste chemoreceptors, mechanoreceptors, sight/smell/thought of food, or irritated GI tract send impulses to salivary nuclei in pons->parasympathetic impulses to salivary glands to secrete saliva
Nucleic acid digestion
Small intestine:
-pancreatic enzymes ribonuclease and deoxyribonuclease digest them down to nucleotides
-brush border enzymes digest them down to phosphate group, pentose sugar, and nitrogenous base
-returned to liver via hepatic portal vein
Serosa or adventitia
Serosa in abdominal cavity, peritoneum
adventitia outside of abdominal cavity (collagen fibers)
Describe the function of cholecystokinin
CCK: secreted in response to fats and proteins in chyme
-targets:
pancreatic acinar cells to increase enzyme production
gall bladder to contract
hepatopancreatic sphincter to open and release
stomach to decrease gastric juices
tells hypothalamus we are full
Urine formation: secretion
-occurs throughout renal tubule and collecting duct
-important for adding substances to urine, disposing of urea/uric acid/ammonia, controlling blood pH, getting rid of excess K+ from Na+/K+ pump
What is the function of hepatocytes?
processes and filters nutrient-rich blood, create bile
Discuss the structure and function of the peritoneum. What are mesenteries and where are they found?
Protection, anchoring, and reduction of friction.
Double serous membrane
found in the abdominal cavity
What are the important structural modifications in the small intestine (think about surface area)?
circular folds, microvilli, and villi
Where are nephrons found within the kidney?
In the cortex and the medulla
What are the accessory organs in the digestive system?
Tongue, teeth, salivary glands, gall bladder, and pancreas
Discuss the different cell types (4) found in the mucosa and the importance of their secretions. How do these secretions work together? What protects the stomach lining from these secretions?
-mucus neck cells: thins acid mucous
-parietal cells- secrete HCl and intrinsic factor (needed for B12 absorption). HCl denatures proteins and activates pepsinogen
-Chief cells: secrete pepsinogen and gastric lipase. Pepsinogen becomes pepsin which is an active protease. Gastric lipase digests milk fats
-Enteroendocrine G cell: secretes gastrin into blood which makes parietal cells secrete more gastric juice
Stomach lining protected by mucus.
distal convoluted tubule, substances are reabsorbed or secreted
-aldosterone causes Na+ absorption and K+ secretion (Na+/K+ pumps)
-parathyroid hormone causes increased calcium reabsorption
-atrial natriuretic peptide causes decreased H2O reabsorption
Discuss the flow of blood and bile through a lobule (and through the liver).
Bile: hepatocytes->bile canaliculi->bile duct->R+L hepatic duct-> common hepatic duct->common bile duct-> duodenum
Blood-> hepatic arteries and portal veins->sinusoids->central vein-> hepatic vein->inferior vena cava
describe salivary glands
minor salivary glands in mouth and tongue but major ones located outside oral cavity
-parotid, submandibular, and sublingual
-contain serous and mucous cells
Urine formation- filtration
Net filtration pressure: pressure responsible for filtration formation. 10mmHg
-glomerular blood hydrostatic pressure: 55 mmHg, pressure of blood against capillary walls
-capsular hydrostatic pressure: 15 mmHg, pressure of fluid in the capsular space pressing against capillary
-blood colloid osmotic pressure: 30mmHg, pressure of blood pulling back in capillary
Glomerular filtration rate: volume of filtration formed by both kidneys per minute
-controlled by renal blood flow
-too high , too low absorption
-too low, too high absorption
What are the functions of the stomach? What type of digestion occurs here?
mechanical and chemical digestion
very little absorption
What organs make up the alimentary canal?
Mouth, oro and laryngopharynx, esophagus, stomach, small intestine, large intestine, rectum, and anus.
Describe the functions of the kidneys
filter blood and remove nitrogen compound waste and drugs
regulate blood plasma makeup (pH, blood pressure, solute concentrations)
hormone production (erythropoietin and renin)
activate vitamin D (cholecalciferol to calcitrol)
absorb Ca2+ from diet
What is digested and what is absorbed in the small intestine?
All macromolecules digested, nutrients absorbed.
What is the difference between the two groups of organs?
One is the main digester, on assists in digesting
Describe the function of secretin
secreted in response to acidity of chyme in duodenum
targets:
-pancreas duct cells to release bicarb
-hepatocytes to make bile
-stomach to decrease gastric juice
How is the alimentary canal innervated?
Intrinsic innervation by the enteric nervous system:
-Submucosal plexus-regulates digestive secretions and reacts to the presence of food
-myenteric plexus- controls motility, peristalsis/segmentation
Extrinsic innervation by the autonomic nervous system:
-sympathetic nervous system-inhibit digestive processes
-parasympathetic nervous system-promotes digestive processes
Hormonal control of renal blood flow and GFR (extrinsic)
Renin secreted by JG cells in response to:
-reduced stretch of JG cells (low BP)
-stimulation of JG cells by activated macula densa cells
-direct stimulation of JG cells by SNS
Renin-angiotensin-aldosterone system
Angiotensin II causes
-vasoconstriction which increases TPR and MAP
-aldosterone secretion from adrenal gland increases Na+/K+ pump in DCT
-thirst center activation in the hypothalamus
- vasoconstriction of afferent arteriole nad efferent arterioles to decrease GFR temporarily
-ADH secretion from pituatarty increases aquaporins in principal cells in collecting duct
How are the mucosa and submucosa specialized in the small intestine?
Mucosa: contains enterocytes (absorptive cells), brush border enzymes, and intestinal glands
Submucosa: duodenal glands and peyer’s patches
How is the secretion of pancreatic juice regulated?
Secretin signals to the duct cells in the pancreas to release bicarb
CCK signals to the pancreas acinar cells to secrete digestive enzymes
Myogenic mechanism (intrinsic)
Regulated by JG cells in the afferent arteriole
If JG cells sense too much stretch the afferent arteriole vasoconstricts to reduce blood flow to glomerulus
If JG cells sense too little stretch, vasodialation of afferent arteriole to increase blood flow to glomerulus
What is glomerular filtration rate (GFR)? Why is regulation of the GFR important?
Glomerular filtration rate: volume of filtration formed by both kidneys per minute
-controlled by renal blood flow
-too high , too low absorption
-too low, too high absorption
Explain the reflexes involved in micturition (urination or voiding).
-distension of bladder activates stretch receptors
-initiates sacral spinal reflex that promotes voiding response
voiding reflex is controlled by pontine micturition center
-increased PSNS causes detrusor muscle to contract and internal urethral sphincter to relax and inhibits somatic motoro activity causing external urethral sphincter to relax
storage reflex (controlled by pontine storage center)
-increased SNS causes detrusor muscle to relax and internal urethral sphincter to contract
-somatic motor activity causing external urethral sphincter to contract
Tubuloglomerular feed back (intrinsic)
Macula densa cells monitor NaCl in filtrate
If GFR is too high, NaCl will be high, MD cells release vasoconstrictors that affect afferent arteriole
If GFR is too low, NaCl will be low, MD cells stop sending vasoconstrictors to afferent arteriole
Describe the process of both peristalsis and segmentation. What is their function
Segmentation- smooth muscle contraction to cause mixing of food with GI juices. Contracts nonadjacent segments for mechanical digestion.
Peristalsis- for propulsion of bolus, esophagus->large intestine
From where are cholecystokinin (CCK) and secretin secreted?
Secreted by enteroendocrine cells in the duodenum.
Discuss the location, structure (and divisions), and function of the large intestine
Surrounds the small intestine in the abdominal cavity
cecum, ascending, transverse, descending, sigmoid, rectum, and anal canal.
Function:
-finish H2O absorption
-synthesize vitamins via bacteria
-form and eliminate feces
What structures make up the juxtaglomerular apparatus (JGA)? What is their function?
Juxtaglomerular cells: mechanoreceptors that sense the stretch of the afferent capillary. secretes renin in response to low BP
Macula densa: chemoreceptors that respond to rate of filtrate flow and concentration of NaCl in filtrate
describe the teeth
-Contains a pulp cavity with blood vessels and nerves, dentin (bonelike tissue, avascular), and enamel which contains calcium-phosphate crystals
-function is mastication
-located in the maxilla and mandible
Discuss the external and internal anatomy of the kidney
external: renal fascia->renal fat pad->fibrous capsule
internal:
-renal cortex: blood filtration
-renal medulla: renal columns, renal pyramids, renal papilla
-renal lobes
-calyces and renal pelvis
-renal hilum
Discuss the gallbladder. What is its main function? Is it involved in bile storage or secretion? How is gallbladder activity regulated?
muscular sac that stores, concentrates, and propels bile into the duodenum. Regulated by secretin and CCK
describe the tongue
-tongue is used to move food in mouth and is a sensory organ. Covered in filiform, circumvallate, and fungiform papillae. Contains taste buds.
-has mucus and serous glands (secrete lingual lipase)
-large amount of skeletal muscle running in lots of directions
loop of henle, substances are reabsorbed or secreted
descending: water reabsorption
ascending: reabsorb NaCl
What is the structure and function of a portal triad
Contains bile duct, branch of the hepatic artery (portal arteriole), and branch of the hepatic portal vein (portal venule)
bile duct: moves bile from hepatocytes to duodenum
artery: brings oxygenated blood
vein: brings deoxygenated nutrient rich blood
Urine formation: reabsorption
-occurs throughout renal tubule and collecting duct, mostly proximal convoluted tubule
-Nat+ active transport, transcellular
-nutrients co transported with Na+, transcellular
-H2O flows by osmosis following solutes, transcellular
-K+, Ca2+, and Mg2+ and urea: diffuse through H2O filled spaces between cells.
-100% of glucose reabsorbed in PCT
-not reabsorbed: creatinin
Discuss the location, structure, and function of the liver.
Largest gland in the body, 4 lobes
500 functions including production of bile, production of cholesterol and lipoproteins, processing blood, makes albumin and clotting proteins, stores glucose as glycogen, releases glucose, stores fat soluble vitamins and iron, detoxification.
connected to the diaphragm and stomach
Describe the structure and function of the esophagus.
All 4 alimentary canal layers
Contains esophageal glands in the submucosa
muscularis external transitions from skeletal to smooth muscle
functions in deglutition- upper esophageal sphincter opens to let in food, moved my peristalsis, passes through the diaphragm and lower esophageal sphincter
What is the structure and function of a lobule?
Filtering blood and producing bile.
-bile canuliculi move bile away from hepatic lobule
-hepatic sinusoids bring blood from artery and portal bring through the lobule to the central vein
-kupffer cells: fixed macrophages in the walls of hepatocytes, phagocytize antigens and old RBC/WBC
Discuss the effects of ADH on the production of concentrated urine.
mild dehydration causes increased blood osmolarity which is detected by osmoreceptors in hypothalamus which secretes antidiuretic hormone from posterior pituitary.
ADH causes increased aquaporins in the collecting duct which increases the reabsorption of water via the osmotic gradient, and a small amount of concentrated urine is produced.
What is bile and where is it made? Where in the digestive tract does it function?
yellow-brown-green solution that contains water, electrolytes (bicarb), and has an alkaline pH
functions in the duodenum
What type of epithelium do you find in each organ?
oral cavity- NKSSE
Esophagus- NKSSE
Stomach- simple columnar w/ goblet cells
Small intestine- simple columnar w/ goblet cells and microvilli
Large intestine- simple columnar w/ a lot of goblet cells
How is bile involved in the breakdown of lipids?
Bile salts made of cholesterol coat fats to increase emulsification (makes smaller particles to increase surface area), and micelle formation around fat molecules increases absorption.
Discuss the location, structure (and divisions), and function of the small intestine
Long tube that runs from pyloric sphincter to ileocecal valve
duodenum-10 inches
jejunum- 3ft
ileum- 6 ft
Function:
mechanical and chemical digestion
absorption of nutrients
Lipid Digestion
ingestion of triglycerides
oral cavity: lingual lipase (inactive)
stomach: lingual lipase (active) and gastric lipase (milk fat)
small intestine:
-bile salts from liver emulsify fats
-pancreatic lipase breaks the triglycerides down into Short fatty acids and glycerol, and long fatty acids, monoglycerides, and diglycerides.
-short fatty acides and glycerol returned to liver via hepatic portal vein
-long fatty acids, monoglycerides, and diglycerides are coated with bile to form micelles, absorbed by enterocytes, rebuilt into triglycerides, coated with proteins to form chylomicrons, released from cell, enter lacteals in villi, and are transported to venous blood.
proximal convoluted tubule, substances are reabsorbed or secreted
Reabsorb:
Na+ active transport
nutrient co-transport (glucose, amino acids, vitamins)
H2O passive transport
Bicarb and other ions passive transport
urea/uric acid passive transport
Describe the structure and function of the nephron.
-series of tubes, renal corpuscle and renal tubules
-filtration, reabsorption, and secretion
Describe the difference between short and long neural reflexes.
Short reflexes- involve intrinsic nerve plexuses
-chemoreceptors+osmoreceptor+mechanoreceptor signals sent to local nerve plexus->smooth muscle or glands are affected
Long reflexes- involve CNS and ANS. external stimuli such as smell or sight->nerve plexuses->effectors
What is net filtration pressure (NFP) and how is it determined?
Net filtration pressure: pressure responsible for filtration formation. 10mmHg
-glomerular blood hydrostatic pressure: 55 mmHg, pressure of blood against capillary walls
-capsular hydrostatic pressure: 15 mmHg, pressure of fluid in the capsular space pressing against capillary
-blood colloid osmotic pressure: 30mmHg, pressure of blood pulling back in capillary
NFP= GBHP-(CHP+BCOP)
What is the countercurrent multiplier and where is it located?
the ascending limb of the loop of henle, which establishes an osmotic gradient in the renal medulla
How is urine drained from a kidney?
renal papillae-> minor calyx-> major calyx-> renal pelvis->ureter via peristalsis
What is the purpose of enterohepatic circulation?
bile salts are reclaimed by the enterohepatic circulation. Reabsorbed in the ileum and brought back to the liver by the portal vein.
Mucosa
Epithelium- nonkeratinized stratified squamous epithelium for protection from abrasion or simple columnar epithelium for absorption
Lamina Propria- loose areolar connective tissue with blood and lymph vessels, elastic fibers, nerves, glands, and malt
muscularis mucosae- thin layer of smooth muscle, creates folds in GI tract, not a major mover.
What enzymes do you find at the brush border, and what do they digest?
5 carb, 3 protein, 2 RNA/DNA
Carbs:
-alpha-dextrinase: breaks down dextrin to glucose
-lactase breaks down lactose to galactose and glucose
-sucrase breaks down sucrose to fructose and galactose
-maltase breaks down maltose into two glucose
Proteins:
-aminopeptidase breaks down amino chain on the amine side
-carboxypeptidase breaks down amino chain from carboxyl side
-dipeptidase breaks down bond between two amino acids
RNA/DNA:
nucleosidase breaks off nitrogenous bases from nucleotides
phosphatase breaks off phosphate group from nucleotide
(sugar pentose left over)
muscularis externa
smooth muscle, inner circular layer, outer longitudinal layer. Used for segmentation and peristalsis. Contains the myenteric nerve plexus.
The stomach contains an additional oblique layer.
Neural control of renal blood flow and GFR (extrinsic)
-PSNS stimulation-> vasodilation of renal blood flow
-SNS stimulation -> vasoconstriction of renal blood flow, renin secretion-> increase MAP
Discuss the motility of the small intestine.
-segmentation takes place when chyme is present
-peristalsis takes place once chyme is absorbed. Initiated when duodenal glands secrete motilin. each eave starts distal to previous wave
Discuss the location, structure, and function of the pancreas.
-deep to the stomach and retroperitoneal, against the duodenum
-both an endocrine and exocrine gland
-sends pancreatic juice to the duodenum
-has a main and accessory pancreatic duct
Describe the structure and function of the rectum and anal canal. What sphincters are located here and how are they controlled?
Rectum has three rectal valves that help prevent simultaneous passage of feces and gas
Anal canal has 2 sphincters
-internal smooth muscle
-external skeletal muscle
What is the function of pancreatic juice?
produced by the acinar cells, enzyme-rich juice is secreted into the duodenum to digest macromolecules.
How is bile release regulated?
Entry of chyme into duodenum stimulates the release of CCK and secretin. Secretin increases bile production in the liver and CCK causes the gallbladder to contract and the hepatopancreatic sphinter to open
Discuss the digestive processes (6) that occur in the alimentary canal. Where does each specifically occur?
-Ingestion- bringing food in, oral cavity
-Propulsion- move substances through digestive tract (esophagus, stomach, small/large intestine)
-Mechanical digestion-physical forces to break apart food. Oral cavity, stomach, and small intestine
-Chemical Digestion- breaking chemical bonds of food we eat w/enzymes, oral cavity, stomach, small intestine
-Absorption- of nutrients and H20 into blood and lymph, small intestine
-Defecation- removal of things not used or digested, anus
Discuss the process of defecation.
-Distenstion of rectal walls by feces causes parasympathetic reflex mediated by spinal cord.
-Mass movement in sigmoid colon and rectum.
-Internal anal sphincter send message to brain
-External anal sphincter initially contracts, relaxes under conscious decision
-Defecation assisted by rectal muscle.
What is the sequence of blood flow through the arteries, capillaries, and veins of the kidneys?
renal artery-> segmental artery->interlobar artery->arcute arteries-> cortical radiate artery-> afferent arteriole-> glomerulus-> efferent arteriole-> vasa recta or peritubular capillaries-> cortical radiate vein, arcute vein-> interlobar vein-> renal vein
How are these involved in the maintenance of concentration gradients in the interstitial fluid of the medulla and in the formation of dilute urine?
countercurrent multiplier-ascending loop of Henle
-solute pumps increase the concentration of interstitial Na2+ deep in the medulla
-allows filtrate to be dilute by the end of the limb
countercurrent exchanger
-by matching the osmolarity in the blood of the IF, solutes are not drawn into the blood and conserve the gradient
What structural modifications are found in the mucosa of the large intestine?
Large amount of goblet cells and enterocytes
